<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div>Header</div>
    <div id="app">
      <button>改变文本</button>
    </div>
    <div>Footer</div>
    <!-- 注意: 部署时，将 "development.js" 替换为 "production.min.js"。-->
    <!-- jsx特点：多个标签最外层（根）只能有一个标签 -->
    <script
      src="https://unpkg.com/react@16/umd/react.development.js"
      crossorigin
    ></script>
    <script
      src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"
      crossorigin
    ></script>
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>

    <script type="text/babel">
      // let message = "Hello World";

      // function btnClick() {
      //   message = "Hello React";
      //   console.log("按钮发生了点击", message);
      //   render();
      // }

      // function render() {
      //   ReactDOM.render(
      //     <div>
      //       <h2>{message}</h2>
      //       <button onClick={btnClick}>改变文本</button>
      //     </div>,
      //     document.getElementById("app")
      //   );
      // }
      // render();
    </script>
  </body>
</html>
